No, most of my tea is loose leaf stuff and the flavors that come from longer steeps are not as good.

(Preface: I embrace and support the "you do you" attitude I've found among Tea People. So I won't say anything you're enjoying is wrong even when I wouldn't do it that way myself!)

Steeps are traditionally short to avoid extracting unwanted flavors that come out of the leaves more slowly. I suggest preparing two smaller pots steeped for different times and taste-test them side by side, to know what difference time makes and which you like better.

Does it count if I make tea, but forget and leave the bag in until its cold?

Depends on the tea.

We have a local gathered tea (sold on stores in Manitoba), made from nettle, goldenrod, and labrador tea. That one we could steep for days if we wanted to, and it only gets better.

My SO likes to add sour fruit in the last minute, after a long steep. Sometimes lingonberry or buckthorn or something, to make it super tart. It's like turning tea into sangria haha.

Yes, but only if I'm making iced tea. The tannins in black tea seem to go well with ice and sugar, my test monkeys say approvingly, "Oh, that's strong."

You must really like tannin. Steeping for a long time brings out lots of tannins. No thank you says I.

Depends on the tea. Some I leave the leaves in all night and top it up if it looks a bit sorry. Some bagged black tea I remove the bag after like 20 seconds.